/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlinePartyInterface.h
Restore party memberships. Intended to be called once during login to restore state from other running instances.
void RestoreParties ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & LocalUserId, const [FOnRestorePartiesComplete](API\Plugins\OnlineSubsystem\Interfaces\FOnRestorePartiesComplete) & CompletionDelegate )